Wells are generally drilled into the ground or seabed to recover natural deposits of oil and gas, as well as other natural resources trapped in geological formations in the Earth's crust. Such wells are drilled using a drill bit attached to a lower end of a drill string or other drill piping. Drilling fluid (“mud”) is pumped from the wellsite surface down through the drill piping to the drill bit. The drilling fluid lubricates and cools the bit, and may additionally carry drill cuttings from the wellbore back to the surface from which the wellbore extends.
A typical drilling rig includes various lifting, rotating, and moving equipment utilized during rig assembly and drilling operations. Fluid actuators, such as hydraulic cylinders and rotary actuators, may power or actuate the moving equipment. Although fluid actuators may provide sufficient speeds and forces, precise movement and positioning of fluid actuators, especially fluid actuators comprising large bores or fluid volumes, is difficult to achieve. For example, controlling large capacity fluid actuators to perform small or short movements may be difficult as fluid directional control valves typically associated with large capacity fluid actuators are not able to meter hydraulic fluid at low flow rates. Inability to perform precise and/or small movements by the fluid actuators may result in difficulty or inability to align portions of the drilling rig and drilling tools during rig assembly and drilling operations, causing operational delays. For example, aligning a mast and substructure raising cylinder (MSRC) with a corresponding pin connector of a mast and substructure of a drill rig may be a problematic and time consuming task, as small movements of each MSRC manipulating cylinder translate to relatively large movements of the MSRC. Also, manual hydraulic directional control valves typically utilized to operate the MSRC manipulating cylinders to adjust the position of the MSRC do not have the ability to cause fine movements of the MSRC manipulating cylinders and, thus, do not provide the ability to make fine adjustments to the position of the MSRC.